(CNN) -- The U.N. nuclear agency said it found traces of uranium from samples retrieved at a Syrian site suspected to be the location of a nuclear site, according to a report posted Thursday on the Institute for Science and International Security Web site.

The site was bombed by Israeli aircraft in September 2007, and the report said Syria says the missiles that destroyed the building at the site were the source of the uranium particles.

The International Atomic Energy Agency's report said that the uranium particles "are of a type not included in Syria's declared inventory of nuclear material" and that "there is a low probability that the uranium was introduced by the use of missiles."

But "the presence of the uranium particles," site imagery and procurement information "need to be fully understood," it said.

Syria needs to provide more information and documentation about "the use and nature" of a building that was bombed and its procurement activities, the report said. And Syria "needs to be transparent by providing access to other locations alleged to be related" to the site.

In the report, IAEA Director General Mohamed ElBaradei urged Israel and other states to make relevant information available to the agency and agree to the IAEA sharing the information with Syria.

In November, the agency asked Israel to provide information in response to Syria's claims that its munitions could have been the source of the uranium particles.

Israel said in a December 24 letter that "it rejects Syrian claims on the matter" and that "Israel could not have been the source of the uranium particles found on the site of the nuclear reactor."

In November, ElBaradei confirmed that his agency found traces of "man-made uranium" at a site in eastern Syria. IAEA inspectors collected soil samples from the Al-Kibar site in June.

ElBaradei said at the time that a report would be issued.

He added that the findings do not necessarily mean the Syrians were building a reactor and cautioned against rushing to judgment. But he urged more "transparency" from the Syrian government in its dealings with the IAEA and deplored the "unilateral" Israeli bombing of the Syrian site.

Syrian authorities have reacted angrily to accusations that they were building a nuclear reactor. Syrian Foreign Minister Walid Moualem suggested that any trace of uranium unearthed at the military site in eastern Syria came from Israeli bombs.